The invention relates to an apparatus for preheating granular ore or the like by means of hot gases, in particular flue gases obtained from a rotary tubular kiln. The apparatus has a shaft which is provided with vertical walls and through which hot gases flow from below in an upward direction, at least one inlet chute provided thereabove, a discharge collector provided underneath thereof and one or more passages which are provided between the shaft and the enlarged inlet cross section of the discharge collector and which serve as gas inlets.
Known apparatus for preheating the feed material such as granular ore or pellets (prior to its introduction into the tubular kiln) wherein the flue gases of the kiln are passed in cross flow through a mass of accumulated material by virtue of horizontal slots in the side walls of the shaft (so-called Venetian blind shaft preheaters), have the disadvantage that the feed material undergoes sintering along the surfaces facing the flow, whereby due to uneven flow through the material the heating is rendered inadequate and uneconomical.
A further known shaft preheater of the aforesaid type, in which gases pass through the shaft upwardly from below also fails to provide an adequate utilization of the heat of the flue gases of the kiln.